How are card structures built?

US card stacker Bryan Berg, 35, made it into the Guinness World Records and then recently broke his own record by building the largest house of free-standing playing cards. The architect successfully created a replica of the Venetian Macau with 2,18,792 cards. These cards are stacked without glue or tape. His method has been tested to support 660 lbs per square foot. The secret is that cards are placed like grids or honeycombs.